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Nissan Pick-ups and Pathfinder 1970-1988

Dual Spark Plug Ignition System



See Figure 1

Z20, Z22, Z24 and Z24i Engines

These engines have two spark plugs per cylinder. This arrangement allows the engine to burn large amounts of recirculated exhaust gases without affecting performance. In fact, the system works so well it improves gas mileage under most circumstances.

Both spark plugs fire simultaneously, which substantially shortens the time required to burn the air/fuel mixture when exhaust gases (EGR) are not being recirculated. When gases are being recirculated, the dual spark plug system brings the ignition level up to that of a single plug system which is not recirculating exhaust gases.

Click image to see an enlarged view

Fig. Fig. 1: Dual point ignition system schematic


The only adjustments necessary are the tune-up and maintenance procedures outlined in General Information & Maintenance and Engine Electrical .